Case Study 1: An Evidence-Based Practice Review … · communication abilities can influence a number of factors in one’s life. ... The Picture Exchange Communication System

Doctorate in Educational and Child Psychology Hannah Lichwa

Case Study 1: An Evidence-Based Practice Review Report

Theme: School Based Interventions for Learning

How effective are methods of aided AAC in improving the functional communication

skills of pre-school children with additional needs?

Are these skills generalisable and maintained?

Summary

This systematic literature review aims to explore the effectiveness of aided methods

of Alternative Augmentative Communication (AAC) in supporting pre-school children

with additional needs in developing their functional communication skills. AAC

describes a number of systems used by a range of individuals to act as an

alternative, or a supplement to augment their speech. Specifically, this review will be

exploring aided methods of AAC that require the use of an additional physical

resource that is external to the person.

Six studies met the inclusion criteria and were reviewed using the Weight of

Evidence Framework (Gough, 2007) and the ‘Quality Indicators Within Single-

Subject Research’ by Horner et al. (2005).

The findings demonstrated that methods of aided AAC were effective in supporting

pre-school children in developing their functional communication skills, and

communicative behaviours, with medium and large effects occurring frequently.

Differences between methods of AAC are discussed, in addition to implications for

use and future directions for research.


Introduction

What is Alternative Augmentative Communication (AAC)?

AAC can involve the use of a range of systems and is used by a wide range of

individuals to either; augment speech acting as a supplementary aide, or as an

alternative to speech, acting as a primary method of communication.

There are two types of AAC, aided and unaided.

Unaided communication does not require any equipment that is external to

the body and involves the use of symbols such as manual signs and gestures.

Aided communication incorporates devices that are external to the individuals

who use them (for example, communication books) and can involve the use of

symbols such as photographs, line drawings, letters, and words.

There are a number of forms of AAC including; the Picture Exchange

Communication System (PECS), Speech Generating Devices (SGD), Makaton

signing, Voice Output Communication Aids (VOCA). Aided communication involves

systems including PECS, SGD and VOCA. Methods of unaided communication,

such as signing, can require learners to use complex motor skills to create signs with

their hands, which may prove difficult with very young children with additional needs

(van der Meer et al., 2011).

Psychological Basis

Communication plays a critical role in development and behaviour. Competency in

communication abilities can influence a number of factors in one’s life. Severe

language impairments in the early years can have lasting consequences in relation

to long term development. In particular when a young child is unable to speak, due to


a developmental delay for example, their ability to express their needs and engage in

social interactions is compromised and this subsequently impacts on their ability to

access an educational environment (Romski, Sevcik, Hyatt, & Cheslock, 2002).

To support individuals with communication difficulties, a range of early interventions

have been devised and implemented, and this includes the use of AAC. The

principles of AAC are rooted in behaviourist psychology approaches. Skinner (1953)

stated that language is learned behaviour that is under the functional control of

environmental variables, and behaviourists regard all behaviour as a response to a

stimulus. AAC stems from this approach, similar to learning spoken language, as it

teaches individuals to carry out a particular communicative behaviour. For example,

when using PECS a symbol needs to be selected in order to get a response. This

behaviour is then reinforced by the response of the other in the interaction.

Although primarily designed to be used as alternatives or methods to augment

speech, the use of AAC has also been stated to facilitate speech development.

Mirenda (2003) stated that the behavioural theory of automatic reinforcement could

act as a potential explanation for this. According to this theory, if AAC is used with

the spoken word and then followed by reinforcement, the frequency of both the use

of AAC and speech production should increase.

The Picture Exchange Communication System (PECS)

PECS is a communication training programme that involves the use of pictures or

symbols as methods of communication (Bondy & Frost, 1994). PECS is being used

nationally and internationally with children and young people with communication

difficulties due to additional needs (Siegel, 2000). A number of factors have been


stated as to why PECS is appealing; it uses few motor skills, unlike methods of

signing; it is portable and low cost to implement; and it is reported that learners of

PECS can master the skills to use it rapidly (Charlop‐Christy, Carpenter, Le,

LeBlanc, & Kellet, 2002).

Speech Generating Devices (SGDs) or Voice Output Communication Aids (VOCA)

The use of VOCAs, or SGDs result in synthesized speech that can be understood

universally, and this can facilitate interactions with others (Schepis & Reid, 1995).

Additional benefits of VOCAs were found in the work of Schlosser, Belfiore, Nigam,

Blischak and Hetzroni (1995). Their research indicated that the addition of voice

output facilitated their participants’ learning of symbols.

Furthermore, Schepis, Reid, Behrmann and Sutton (1998) evaluated the effects of

VOCA in relation to communicative behaviours in young children with autism. Their

findings indicated that the use of a VOCA supported an increase in communicative

interactions. SGDs can be personalised to specific user groups and are often

programmed to contain and produce age-appropriate and contextually relevant

content with minimal effort (Schlosser, Sigafoos & Koul, 2009). In addition to this, the

speech-output provided by the SGD may also provide useful feedback to the users

(Boesch, Wendt, Subramanian, & Hsu, 2013).

Rationale

“Speech, language and communication is the most important thing in all our children

... It’s their key to life” (Bercow, 2008). Communication is fundamental in relation to

education, and in particular for pre-school children as early experiences of


communication can impact their subsequent experiences (DfE, 2015). A method of

AAC that allows an individual to communicate is invaluable. Having a functional

communication method or system can positively influence an individual’s ability to

make choices and subsequently can improve their overall quality of life, and this

relates to their fundamental human rights (Bush & Scott, 2009; Hamm & Mirenda,

2006). Furthermore, Pituch et al. (2011) found that in a survey of 90 parents,

communication skills were selected as being in the top 10 educational priorities for

children with additional needs.

In relation to pre-school children and the need for additional communication support,

Binger & Light (2006) gathered the demographic information of pre-schoolers who

were stated to require AAC. Their results indicated that approximately 12% of pre-

schoolers in receipt of special educational services required AAC, and found these

children came from a wide range of backgrounds relating to both race and disability,

and used a range of AAC. They concluded that these results indicated that settings

should ensure they are prepared and equipped to provide appropriate support to

children who require AAC.

In light of this, settings may wish to identify which AAC systems are most effective

for pre-school children with additional needs. There are a number of systems that

could be implemented, each with its own benefits and limitations and this forms the

basis for this review.

Relevance to Educational Psychology (EP) Practice

In the SEND Code of Practice (DfE, 2015), guidance is described in relation to

assessing progress in the early years. It is advised that assessment should look at

the seven areas of learning, of which ‘communication and language’ is one. The


SEND Code of Practice also states the importance of identifying and implementing

any special educational provision, and failure to do so, may result in subsequent

difficulties and frustration with learning and also possible loss of self-esteem.

AAC is referred to in the new Code of Practice (DfE, 2015), when carrying out an

assessment, the local authority should seek the child or young person’s views, and

should do so using appropriate methods that may include a method of AAC. In

addition to this, when describing a number of reasonable steps that can be taken to

support children and young people, they stated; “providing the child with a channel of

communication” is key (DfE, 2015).

In relation to EP practice, according to the Bercow Report (2008), around 7% of 5

year olds starting school in England have significant speech and/or language

difficulties, and around 1% have severe and complex speech, language and

communication needs. These children may have difficulties understanding what is

said by others, and have little spoken language and are more likely to be incoherent

when they start school. The children will often need methods of AAC in order to

communicate, and are likely to need specialist help in the long term.

The Rose Review (2005) emphasised the importance of speaking and listening

skills, not only for literacy, but for the entire curriculum. In addition to this, in the

research conducted by Snowling, Bishop, Stothard, Chipchase and Kaplan (2006) it

was found that children who had persistent and severe speech and language delays

and difficulties and low non-verbal IQ at age 5.5 years, were at higher risk of

psychiatric morbidity in adolescence, again highlighting the impact that difficulties

with communication can have later in life. EPs therefore play a key role in helping to

support those with communication needs to ensure access to appropriate learning

opportunities to maximise potential outcomes. EPs may become involved with


children and young people experiencing communication difficulties, and through

assessment they can provide information relating to particular aspects of

communication they may be experiencing difficulties in, for example, expressive

language skills. Based on the findings from their assessments, EPs will then provide

recommendations on how the child can be best supported in relation to these needs,

and in some instances, a communication aid may be recommended.

Review Question

Based on the research above, this review aims to explore;

How effective are methods of aided AAC in improving the functional

communication skills of pre-school children with additional needs?

Are these communication skills generalisable and maintained?

Critical Review of the Evidence Base

Literature Search

Systematic searches of electronic databases PsychINFO, Educational Resource

Information Centre (ERIC) and Web of Science were carried out during December

2015 using the search terms presented in Table 1.

In order to ensure that the studies included in this review were suitable for the

purpose of the question, inclusion and exclusion criteria were devised and applied to

the identified studies. These criteria are presented in Table 2 with a rationale for

each criterion. Studies that met the inclusion criteria and are included in this review

are presented in Table 3. As illustrated in Figure 1 the study selection process

involved a number of stages. Initially, duplicates were removed, and a further 58

studies were excluded following a screen of the title and abstract. Following this, the


35 studies that were remaining were screened at full text. When the inclusion and

exclusion criteria were applied, 29 studies were excluded and the remaining 6

studies were included in this review.

Table 1: Search terms and results

Search terms ERIC Results PsychInfoResults

Web of ScienceResults

AAC AND preschoolAND disabilities

5 10 51

PECS AND preschoolAND disabilities

6 5 13

SGD AND preschoolAND disabilities

1 1 9

speech generatingdevices AND preschool

AND disabilities

3 1 16

VOCA AND preschoolAND disabilities

2 2 8

alternative augmentativecommunication ANDpreschoolers AND

disabilities

7 0 9


Figure 1: Study Selection Process

Articles identified from electronic

databases:

Psychinfo = 19

ERIC = 24

Web of Science= 106

Total = 149

Papers excluded

Did not meet inclusion criteria:

n=58

Duplicates:

n= 56

Papers reviewed at full text:

n=35

Papers excluded:

Did not meet inclusion criteria:

n=29

Articles identified for thereview:

n=6


Table 2: Inclusion and exclusion criteria

Inclusion Exclusion Rationale

1. Type of

publication

a) Must be in a peer

reviewed-journal or

have been submitted

for peer-review

a) Is not or has not been

submitted for peer review i.e.

Books, chapters.

Peer reviewers assess the quality of a

study and therefore the study in these

journals is likely to meet the required

standards.

2. Design a) Uses primary

empirical quantitative

data

a) Meta-analyses

b) Research reviews

c) Qualitative design

This review is exploring primary empirical

data.

3. Intervention a) Use of aided AAC

including; SGD,

PECS & VOCA.

b) Targeting

communication skills

a) No use of AAC

b) Use of unaided AAC without

equipment, e.g. Makaton,

signing

The review question is based on exploring

the effectiveness of aided AAC using

equipment that is external to the individual.

The review is aiming to explore school

based interventions, therefore all


Inclusion Exclusion Rationale

Intervention c) Targeting non-communicative

skills

d) Carried out at home

participants need to be attending a setting

and the intervention must be carried out in

the setting.

4. Participants a) Pre-schoolers

b) Additional needs

c) Attending provision

e.g. nursery/pre-

school

a) Above 5 years old

b) Not attending provision

c) No additional needs

The review question is based on a specific

age group, pre-schoolers, with additional

needs. In particular to explore the

effectiveness of early intervention using

aided AAC.

5. Language and

setting

a) Must be written in

English.

b) No restrictions on

country the research

has taken place.

a) Study is not written in English Reviewer does not have the resources to

access other languages.

6. Date of

publication

a) Studies published

after 2000

a) Studies published before 2000 In order to ensure the review has the most

up to date information, studies published in

the past 15 years are to be included.


Table 3: Final list of included studies

Included studies

Beck, A.R., Stoner, J.B, Bock, S.J & Parton,T. (2008). Comparison of PECS and

the use of a VOCA: A replication. Education and Training in Developmental

Disabilities, 43(2), 198-216.

Binger, C., & Light, J. (2007). The effect of aided AAC modeling on the expression

of multi-symbol messages by preschoolers who use AAC. Augmentative and

Alternative Communication, 23(1), 30-43.

Bock, S. J., Stoner, J. B., Beck, A. R., Hanley, L., & Prochnow, J. (2005).

Increasing functional communication in non-speaking preschool children:

Comparison of PECS and VOCA. Education and Training in Developmental

Disabilities, 264-278.

Cihak, D.F., Smith, C.C., Cornett, A., & Coleman, M.B. (2012). The use of video

modeling with the picture exchange communication system to increase

independent communicative initiations in preschoolers with autism and

developmental delays. Focus on Autism and Other Developmental Disabilities, 27,

3-11.

Johnston, S.S., McDonnell, A.P., Nelson, C., & Magnavito, A. (2003). Teaching

functional communication skills using augmentative and alternative communication

in inclusive settings. Journal of Early Intervention, 25, 263-280.

Trembath, D., Balandin, S., Togher, L., & Stancliffe, R. J. (2009). Peer-mediated

teaching and augmentative and alternative communication for preschool-aged

children with autism. Journal of Intellectual and Developmental Disability, 34(2),

173-186.


Weight of Evidence (WoE)

The WoE framework (Gough, 2007) was used to appraise the quality and relevance

of the studies included in the review.

WoE A involved generic judgements about the coherence and integrity of the

evidence being made. For this purpose the ‘Quality Indicators Within Single-Subject

Research’ checklist by Horner et al. (2005) was used to code different features of the

study systematically. Through using the Horner coding protocols, it was possible to

award each study a numerical rating for each key feature outlined in Appendix 3.

This rating system then allowed a mean rating to be calculated for each study. WoE

B involved specific judgements about the suitability of the research designs in

relation to the review question. WoE C required specific judgements about the

relevance of the focus of the evidence for the review question, to be made.

This framework then allowed the three sets of ratings (WoE A, B & C) to be

averaged to give an overall assessment of the extent to which each study

contributes to the review question, WoE D. Table 4 summarises the overall WoE.


Table 4: Critical appraisal for quality and relevance

Studies WoE AQuality of

methodology

WoE BRelevance ofMethodology

WoE CRelevance ofevidence tothe reviewquestion

WoE DOverall

weight ofevidence

Beck, Stoner,Bock & Parton

(2008)

Medium(1.8)

Medium(2)

Medium(2)

Medium(1.9)

Binger & Light(2007)

High(2.7)

Medium(2)

High(3)

High(2.6)

Bock, Stoner,Beck, Hanley& Prochnow

(2005)

High(2.5)

Medium(2)

Medium(2)

Medium(2.2)

Cihak, Smith,Cornett, &Coleman

(2012)

Medium(2.3)

Medium(2)

Medium(2)

Medium(2.1)

Johnston,McDonell,Nelson &Magnavito

(2003)

Medium(2.1)

Medium(2)

High(3)

Medium(2.4)

Trembath,Balandin,Togher,

Stancliffe(2009)

Medium(2.1)

Medium(2)

High(3)

Medium(2.4)

Low: Below 1.5; Medium: 1.6-2.4; High 2.5 or above

Participants

The number of participants in the included studies ranged from 3-6 and they were

recruited from the USA (n=5) and Australia (n=1). When included studies were

collated there were 25 children in total. All participants were pre-school children

under 5 years old and were attending pre-school settings. The collated sample

consisted of 18 males and 5 females. All participants were described as having

additional needs; autism (n=7), developmental delay (n=11), Cerebral Palsy (n=1),


severe multiple disabilities (n=1), Pervasive Developmental Disorder-Not Otherwise

Specified (n=1), Speech & Language impairment/apraxia (n=1), Prader-Willi

Syndrome (n=1), Downs Syndrome (n=1) and DiGeorge Syndrome (n=1). The

overall sample was primarily dominated by individuals with developmental

disabilities, although did include participants with physical difficulties (e.g. Cerebral

Palsy). In addition to this, there was also a gender imbalance within the sample, as

the majority of the sample were male.

Design

All studies in this review used single case experimental designs. More specifically,

the designs used in the studies included an alternating treatments design; (Beck et

al., 2008; Bock et al., 2005; Cihak et al., 2012); a multiple baseline design (Johnston

et al., 2003; Trembath et al., 2009); and a single subject, multiple probe research

design (Binger & Light, 2007).

Research using a single case design enables investigation using small sample sizes.

Single case designs can be used to establish causal implications and as they clearly

document experimental control, they can be used to establish evidence based

practices, similar to randomised control trials (Horner et al., 2005). In relation to

research within education, single case designs can be beneficial. As the data

collected focuses on individuals, these designs are suitable for heterogeneous

populations, which can be particularly useful when carrying out research within

special education. However as small samples are used in these designs, the results

they generate must be generalised with caution, and this is reflected in none of the

included studies receiving a high rating for WoE B.


Each study in the review was rated for methodological quality (WoE A) using a

coding protocol relevant to the study design (Horner et al., 2005). Within single case

design studies, the baseline condition acts as a within-participant control, similar to

how a control group is used within a group design study (Horner et al., 2005). All

studies established a baseline of the participants’ use of the identified method of

aided AAC to be used within their study.

Due to the nature of this review, aiming to explore the effectiveness of methods of

aided AAC in developing the functional communication skills, it is important to

assess if the effects of implementing this intervention are generalised or maintained.

The overall aim of this intervention is to generalise the use of aided AAC to

communicate functionally with others across a range of setting. Four out of the six

reviewed studies did investigate generalisation and maintenance of the dependent

variable within participants.

All designs provided a clearly operationalized definition of the target behaviours to be

measured and each dependent variable was quantifiable. All six studies used more

than one observer to record observations to minimise bias and increase reliability,

and reported inter-observer agreement rates of at least 80% (Horner et al., 2005), all

of which positively contributed to WoE A ratings.

Intervention

All studies included in this review used a method of aided AAC during the

intervention phases. These included; PECS, VOCA, SGD, PECS and visual

modelling and communication boards/symbols.

In the Johnston et al. (2003) study, each of the participants were provided with an

AAC device that was designed to address their specified communication goals.


These devices were individualised for the participants in order to maximise their

abilities and address their communication needs therefore was rated highly on WoE

C, as the significance of the use of AAC was established. Two of the participants

used a single-switch voice output device (VOCA), and the third participant used

symbols in the form of coloured laminated line drawings from the Picture

Communication Symbols Collection (Johnson, 1994).

In the studies by Beck et al. (2008) & Bock et al. (2005) VOCA and PECS were

used. VOCA interventions used a ‘GoTalk,’ a lightweight digitised AAC device with a

built in handle and nine static locations separated by a keyguard. PECS included the

use of a 3 ring binder with a Velcro strip attached to the front. Both used symbols

that were laminated coloured pictures with the name of the picture printed above it.

Two of the participants in the Binger & Light (2007) study used specific VOCAs

(Mercury ™; EasyTalk ™) and the final participant used a communication board, with

printed symbols and placed in protective laminated sheets.

Participants in the Cihak et al. (2012) study used PECS, and the picture icons were

attached, with Velcro, to a notebook. This study also included a video modelling

aspect. During the VM and PECS intervention participants were shown a video of a

peer using PECS to request a desired item on a laptop computer, and the video was

chosen based on the setting of the upcoming activity the participant was to engage

in. Immediately following VM procedures, PECS instruction began as described in

the PECS-only intervention. This descriptive account provided by Cihak et al. (2012)

positively contributed to the medium rating for WoE A in relation to clearly describing

conditions that can be easily replicated.


All participants in the Trembath et al. (2009) study used a SGD during the

intervention phase. Specifically, a Talara-32™ SGD was used with spoken words

and messages in a digitised speech format that were represented using colour

Boardmaker ™ symbols.

Although a number of the studies utilised a VOCA/SGD, the device used in the

Binger & Light (2007) study, differed from those used in the other studies as it used a

single switch output device. In contrast to this, the other devices had a number of

symbols on corresponding buttons that participants could choose to select. This is

important to consider as participants using the single switch output device could

have been more limited in their communicative behaviours, as the other

VOCAs/SGDs had a number of options to select, that resulted in varying outputs and

corresponded to different objects or items. However, the use of the single output

devices could be simpler for the participants to use as no demands are placed on

them in relation to choice making and representation of information, and therefore

these single switch devices could be more appropriate for individuals with complex

needs who could have difficulties with a multiple option VOCA/SGD.

Measures

Data was recorded and measured in various ways across the studies. The following

descriptors were used to record the use of AAC; percentage of accuracy using AAC;

(Bock et al., 2005; Beck et al., 2008); percentage of independent exchanges (Cihak

et al., 2012); percentage correct use of symbolic communication (Johnston et al.,

2003); communicative behaviours per minute (Trembath et al., 2009); and number of

multi-symbol messages within 15-min play sessions (Binger & Light, 2007).


In relation to the recording and measurement of data, the studies did vary. The

majority of studies were focused on the accuracy and use of the method of AAC,

whereas one study, (Trembath et al., 2009) measured all communicative behaviours.

Findings

Percentage of all non-overlapping data (PAND) was used to calculate the effect

sizes for each case in the studies included for this review.

Table 5: Percentage of all non-overlapping Data (PAND) for interventions usingVOCA & SGD

Participant Study Baseline vsintervention

Baseline vsMaintenance &Generalisation

Intervention vsMaintenance &Generalisation

V1 Binger & Light 100% 88% 62%T1 Binger & Light 100% 100% 91%R1 Binger & Light 97% N/A N/AJ1 Johnston et al., 92% 100% 86%M1 Johnston et al., 60% N/A N/AD2 Beck et al., 71% N/A N/AS2 Beck et al., 75% N/A N/AM2 Beck et al., 0% N/A N/AB2 Beck et al., 0% N/A N/AD2 Bock et al., 78% 100% 92%J3 Bock et al., 80% 80% 92%R2 Bock et al., 78% 83% 85%C2 Bock et al., 83% 100% 81%A3 Bock et al., 91% 100% 81%N3 Bock et al., 100% 100% 81%J2 Trembath et al., 76% 100% 91%A2 Trembath et al., 93% 81% 100%S1 Trembath et al., 100% 66% 100%


Table 6: Percentage of all non-overlapping Data (PAND) for interventions usingPECS & VM




A1 Cihak et al., 100% 100% 54%B1 Cihak et al., 100% 100% 33%D1 Cihak et al., 100% 100% 64%C1 Cihak et al., 100% 100% 75%

Table 7: Percentage of all non-overlapping Data (PAND) for interventions using –PECS only




A1 Cihak et al., 100% N/A N/AB1 Cihak et al., 100% N/A N/AD1 Cihak et al., 100% N/A N/AC1 Cihak et al., 100% N/A N/AD2 Beck et al., 86% N/A N/AS2 Beck et al., 87% N/A N/AM2 Beck et al., 78% N/A N/AB2 Beck et al., 73% N/A N/AD2 Bock et al., 86% 100% 86%J3 Bock et al., 85% 100% 78%R2 Bock et al., 92% 83% 85%C2 Bock et al., 100% 100% 81%A3 Bock et al., 100% 100% 90%N2 Bock et al., 100% 100% 81%

Table 8: Percentage of all non-overlapping Data (PAND) for interventions usingCommunication Board/Symbols




N1 Binger & Light 100% 92% 80%R1 Binger & Light 94% 91% 80%S1 Johnston et al., 100% 100% 80%


Overall, the results provided from the included studies indicate that aided AAC was

effective in improving functional communication skills in pre-school children with

additional needs with high, medium and moderate effects frequently demonstrated in

‘baseline & intervention’ scores for all methods of aided AAC. In relation to the

methodological relevance of the included studies, they were all given low or medium

ratings. This is important to note as results should be interpreted with caution,

particularly in relation to generalisability of the findings. Studies that utilised an active

comparison group, for example, randomised control trials, would have received a

high rating for methodological relevance and could have provided more reliable data.

As seen in Table 5, for 2 participants there was no effect found for the use of VOCA.

This is important to note, as this demonstrates that although positive outcomes have

been found, it is not possible to assume that AAC will be accessible for all

individuals. The Beck et al. (2008) study that provided these results received a low

rating for methodological relevance, and this should be considered in relation to

trustworthiness of the data.

Effects for PECS, and PECS & VM showed the highest effects in ‘baseline &

intervention’ scores, with effects ranging from 73% (moderate) to 100% (high).

The Beck et al. (2008) research showed the most within study variance, with

intervention effectiveness ranging from no effect to very effective.

The research carried out by Bock et al. (2005) showed the strongest results for

PECS with all of these participants demonstrating large effects (100%) in ‘baseline &

intervention’ and ‘baseline & maintenance/generalisation’. Table 10 shows overall

effect sizes split by intervention. Both of the studies that used communication

boards/symbols (Binger & Light; Johnston et al.,) rated highly on WoE C and high


and medium effects were found across conditions. As they received these high

ratings, this is promising in relation to the trustworthiness of the data and its positive

results.

Table 9: Percentile distributions & descriptors for PAND (Parker et al., 2011)

PercentileRank

10th 25th 50th 75th 90th

PAND .20 .38 .64 .86 1.00

Effect Size No effect Small Moderate Medium Large

Table 10: Overall mean effect sizes split by intervention

Effect size VOCA &SGD

PECS PECS &VM

CommunicationBoard/Symbols

Baseline vs intervention 76.66%

(Medium)

91.92%

(Large)

100%

(Large)

98%

(Large)

Baseline vsmaintenance/generalisation

91.5%

(Large)

97.16%

(Large)

100%

(Large)

94.33%

(Large)

Intervention vsmaintenance/generalisation

86.83%

(Large)

83.5%

(Medium)

56.5%

(Moderate)

80%

(Medium)

Maintenance & Generalisation

Four of the six included studies recorded maintenance and generalisation data for

the communicative behaviour rationalised as their dependent variable and this was

reflected in ratings for WoE A & B. Upon exploration of the data, a number of studies

showed high effects (91-100%) between ‘baseline & maintenance/generalisation’


phases. To explore this further, PAND was also calculated between ‘intervention &

maintenance/generalisation’ phases. The results were more varied when comparing

these phases, with effects ranging from large (VOCA/SGD), to moderate (PECS &

VM) and medium (PECS; Communication Board/Symbols).

This was important to explore as anticipated, the majority of participants made

positive gains from baseline to intervention and maintenance/generalisation phases.

Comparing intervention phases was also necessary as during intervention

participants are supported in developing the skill, and it was important to explore if

this skill is maintained over time, particularly following the implementation and

subsequent removal of the support with the intervention.

Comparing these phases on individual cases also offered more variability within the

findings. Excluding the 2 participants for which no effect of intervention was found, in

the Cihak et al. (2012) study, the lowest effects of the review were demonstrated in

‘intervention & maintenance/generalisation’, at 33 & 54% respectively, however, as

with the Beck et al. (2008) study, this study also received a low rating for

methodological relevance. In contrast, to the high (100%) effects found for

participants when comparing other phases. It is therefore important to consider

individual differences which exist regarding preference and success with the different

methods of AAC. Only one of the included studies received an overall WoE D rating

of high (Binger & Light, 2007). The remaining 5 included studies received medium

ratings for WoE D.

Conclusions

This review examined six studies, all of which utilised a single case design to explore

the effectiveness of aided AAC in increasing functional communication skills in pre-


school children with additional needs. Overall, the reviewed studies provided

promising evidence to support the effectiveness of aided AAC for increasing the

child’s functional communication skills. However, the presence of slight variability in

data does raise questions regarding accessibility of these methods of AAC for all

children, as for some participants, there was no effect of intervention in increasing

functional communication skills.

From the combined results, PECS appeared to be the most effective form of aided

AAC in improving functional communication skills. However, the generalisability of

the results from the studies must be considered. Although all of the studies in this

review showed medium or large effects for increases in functional communication

skills, the small number of participants used in these studies can make it difficult to

establish if other participants would experience the same results. This is particularly

pertinent when within the same study there are participants who have achieved small

or no effect from the intervention.

Children with developmental disabilities can sometimes fail to develop the ability to

speak (National Research Council, 2001), therefore a method of AAC that can

provide them with a means of functional communication can result in significant

benefits to a child or young person’s education. Due to this, the development of

these skills in the early years appears to be promising intervention for pre-school

children presenting with difficulties in relation to their expressive communication

skills. In relation to exploring if aided or unaided methods of AAC are more

appropriate, van der Meer et al. (2012) stated that it may be more difficult to learn

methods of signing as they require recall memory whereas graphic symbols may be

less demanding on children’s working memory (Iacono & Duncum, 1995). In relation


to pre-school children in particular, these findings could also be supportive of the use

of aided AAC rather than unaided AAC, due to greater demands placed on

individuals when using unaided methods of AAC.

Limitations

Although the use of single case research has a number of benefits, and recording at

various intervals support their robustness, there are limitations of research utilising

the designs. Generalisability of findings should be approached with caution as the

samples used in these studies are often heterogeneous. Although a range of

additional needs/diagnoses were included in this review, the overall sample was

dominated by individuals without specific physical disabilities. The use of aided AAC

requires the use of fine (PECS/symbols) and gross (VOCA/SGD) motor skills.

Although these aided methods of AAC are deemed to be easier to use, and more

accessible than unaided methods of AAC (e.g. Makaton signing) some degree of

motor skill proficiency is necessary (van der Meer et al., 2012).

Recommendations

This systematic literature review aimed to explore if methods of aided AAC

supported pre-school children with additional needs in improving their functional

communication skills. The positive increases in functional communication skills for

the participants in this study are promising, as the majority of participants showed an

increase in functional communication skills using methods of aided AAC. Results did

vary depending on which method of AAC participants were using, and variables

relating to the reasons for this could also be explored. In light of the findings from this


review, EPs may wish to tentatively recommend the use of aided AAC for young pre-

school children having difficulties with communication as the results from the collated

studies have demonstrated positive results, and they place less demand on motor

skills than unaided methods of AAC.

In relation to the practical use of AAC with pre-school children, it is important to

consider a number of factors. The varying needs of the children should be carefully

considered before implementation of an AAC system to ensure that it is appropriate

for both their communication need and also cognitive functioning. For example, very

young children may have difficulties understanding the external representation of

pictures or symbols in relation to objects, and in such cases, some AAC systems

may not be effective. Due to this, it is important to ensure that the AAC system is

both accessible and meaningful for the individual child to maximise possible

success.

To conclude, whilst the current evidence suggests aided AAC can be effective in

increasing functional communication skills for pre-school children with additional

needs, further research in this area would be beneficial. Firstly, due to small sample

sizes, more evidence would be needed to explore if these results could be

generalised to a wider range of pre-school children with additional needs. In addition

to this, research in relation to maintenance of the taught communication skills, and

generalisation across a number of contexts would be beneficial. Research of this

nature would further strengthen the evidence base for the use of aided AAC for

children with additional needs.


References

Beck, A. R., Stoner, J. B., Bock, S. J., & Parton, T. (2008). Comparison of PECS andthe use of a VOCA: A replication. Education and Training in DevelopmentalDisabilities, 198-216.

Bercow, J, MP. (2008). The Bercow Report: A Review of Services for Children andYoung People with Speech, Language and Communication Needs.Nottingham: DCSF Publications.

Binger, C., & Light, J. (2006). Demographics of preschoolers who require AAC.Language, Speech, and Hearing Services in Schools, 37(3), 200-208.

Binger, C., & Light, J. (2007). The effect of aided AAC modeling on the expression ofmulti-symbol messages by preschoolers who use AAC. Augmentative andAlternative Communication, 23(1), 30-43.

Bock, S. J., Stoner, J. B., Beck, A. R., Hanley, L., & Prochnow, J. (2005). Increasingfunctional communication in non-speaking preschool children: Comparison ofPECS and VOCA. Education and Training in Developmental Disabilities, 264-278.

Boesch, M. C., Wendt, O., Subramanian, A., & Hsu, N. (2013). Comparative efficacyof the Picture Exchange Communication System (PECS) versus a speech-generating device: Effects on requesting skills. Research in Autism SpectrumDisorders, 7(3), 480-493.

Bondy, A. S., & Frost, L. A. (1994). The picture exchange communication system.Focus on Autism and Other Developmental Disabilities, 9(3), 1-19.

Bush, M., & Scott, R. (2009). No Voice, No Choice. London: Scope UK.

Charlop‐Christy, M. H., Carpenter, M., Le, L., LeBlanc, L. A., & Kellet, K. (2002).Using the picture exchange communication system (PECS) with children with

autism: Assessment of PECS acquisition, speech, social‐communicativebehavior, and problem behavior. Journal of applied behavior analysis, 35(3),213-231.

Cihak, D.F., Smith, C,C., Cornett, A., & Coleman, M,B. (2012). The use of videomodeling with the picture exchange communication system to increaseindependent communicative initiations in preschoolers with autism anddevelopmental delays. Focus on Autism and Other DevelopmentalDisabilities, 27, 3-11.

DfE, D. (2015). SEND Code of Practice 0–25 Years. London: Department forEducation, Department of Health.Dogoe, M. S., Banda, D. R., & Lock, R. H.(2010). Acquisition and generalization of the picture exchange communicationsystem behaviors across settings, persons, and stimulus classes with threestudents with autism. Education and Training in Autism and DevelopmentalDisabilities, 216-229.


Evans, D. (2003). Hierarchy of evidence: A framework for ranking evidenceevaluating healthcare interventions. Journal of Clinical Nursing, 12, 77–84.

Gough, D. (2007). Weight of evidence: a framework for the appraisal of the qualityand relevance of evidence. Research papers in education, 22(2), 213-228.

Hamm, B., & Mirenda, P. (2006). Post school quality of life for individuals withdevelopmental disabilities who use AAC. Augmentative and AlternativeCommunication, 22(2), 134-147.

Horner, R. H., Carr, E. G., Halle, J., McGee, G., Odom, S., & Wolery, M. (2005). Theuse of single-subject research to identify evidence-based practice in specialeducation. Exceptional children, 71(2), 165-179.

Iacono, T., & Duncum, J. (1995). Comparison of sign alone and in combination withan electronic communication device in early language intervention: Casestudy. Augmentative and Alternative Communication, 11, 249–259.

Johnson, R. (1994). The Picture Communication Symbols Collection. Solana Beach,CA: Mayer Johnson.

Johnston, S. S., McDonnell, A. P., Nelson, C., & Magnavito, A. (2003). Teachingfunctional communication skills using augmentative and alternativecommunication in inclusive settings. Journal of Early Intervention, 25(4), 263-280.

Mirenda, P. (2003). Toward functional augmentative and alternative communicationfor students with autism: Manual signs, graphic symbols, and voice outputcommunication aids. Language, Speech, and Hearing Services in Schools,34, 203–216.

National Research Council. (2001). Educating children with autism. Washington, DC:Henry (Joseph) Press.

Parker, R. I., Vannest, K. J., & Davis, J. L. (2011). Effect Size in Single-CaseResearch: A Review of Nine Nonoverlap Techniques. Behavior Modification,35, 303–322.

Pituch, K. A., Green, V. A., Didden, R., Lang, R., O’Reilly, M. F., Lancioni, G. E., &Sigafoos, J. (2011). Parent reported treatment priorities for children withautism spectrum disorders. Research in Autism Spectrum Disorders, 5, 135–143.

Romski, M. A., Sevcik, R. A., Hyatt, A. M., & Cheslock, M. (2002). A continuum ofAAC language intervention strategies for beginning communicators.Exemplary practices for beginning communicators: Implications for AAC, 1-23.

Rose, J. (2005). Independent review of the teaching of early reading: Interim report.Department for education and skills.


Schepis, M. M., Reid, D. H., Behrmann, M. M., & Sutton, K. A. (1998). Increasingcommunicative interactions of young children with autism using a voice outputcommunication aid and naturalistic teaching. Journal of Applied BehaviorAnalysis, 31(4), 561-578.

Schepis, M. M., & Reid, D. H. (1995). Effects of a voice output communication aid oninteractions between support personnel and an individual with multipledisabilities. Journal of Applied Behavior Analysis, 28(1), 73-77.

Schlosser, R. W., Sigafoos, J., & Koul, R. (2009). Speech output and speech-generating devices in autism spectrum disorders. Autism spectrum disordersand AAC, 141-170.

Schlosser, R. W., Belfiore, P. J., Nigam, R., Blischak, D., & Hetzroni, O. (1995). Theeffects of speech output technology in the learning of graphic symbols.Journal of Applied Behavior Analysis, 28(4), 537-549.

Siegel, B. (2000). Behavioral and educational treatments for autism spectrumdisorders. The Advocate, 33, 22–25.

Skinner, B. F. (1953). Science and behavior. New York: Macmillan.

Snowling, M. J., Bishop, D. V. M., Stothard, S. E., Chipchase, B., & Kaplan, C.(2006). Psychosocial outcomes at 15 years of children with a preschoolhistory of speech‐language impairment. Journal of Child Psychology andPsychiatry, 47(8), 759-765.

Trembath, D., Balandin, S., Togher, L., & Stancliffe, R. J. (2009). Peer-mediatedteaching and augmentative and alternative communication for preschool-agedchildren with autism. Journal of Intellectual and Developmental Disability,34(2), 173-186.

van der Meer, L., Didden, R., Sutherland, D., O’Reilly, M., Lancioni, G., & Sigafoos,J. (2012). Comparing three augmentative and alternative communicationmodes for children with developmental disabilities. Journal of Developmentaland Physical Disabilities, 24(5), 451-468

Warren, S. F., & Abbeduto, L. (2007). Introduction to communication and languagedevelopment and intervention. Mental Retardation and DevelopmentalDisabilities Research Reviews, 13(1), 1-2.


Appendices

Appendix 1: Excluded studies screened at full text

Study Reference Excludedbased on:

Barker, R. M., Akaba, S., Brady, N. C., & Thiemann-Bourque, K. (2013).Support for AAC use in preschool, and growth in language skills, for youngchildren with developmental disabilities. Augmentative and AlternativeCommunication, 29(4), 334-346.

Inclusioncriteria: 2A

Binger, C., & Light, J. (2006). Demographics of preschoolers who requireAAC. Language, Speech, and Hearing Services in Schools, 37, 200-208.

Inclusioncriteria: 2A

Brady, N.C., Thiemann-Bourque, K., Fleming, K.,& Matthews, K. (2013).Predicting language outcomes for children learning augmentative andalternative communication: Child and environmental factors. Journal ofSpeech, Language, and Hearing Research, 56, 1595-1612.

Exclusioncriteria: 3B

Charman, Tony [Ed]. (2004). Editorial Preface. Journal of Autism andDevelopmental Disorders, 34, 365-366.

ExclusionCriteria: 1A

Cosbey, J. E., & Johnston, S. (2006). Using a single-switch voice outputcommunication aid to increase social access for children with severedisabilities in inclusive classrooms. Research and Practice for Persons withSevere Disabilities, 31(2), 144-156.


Dropik, P. L., & Reichle, J. (2008). Comparison of accuracy and efficiencyof directed scanning and group-item scanning for augmentativecommunication selection techniques with typically developingpreschoolers. American Journal of Speech-Language Pathology, 17(1), 35-47.

ExclusionCriteria:4C

Fallon, K.A., Light, J.C., & Paige, T.K. (2001). Enhancing vocabularyselection for preschoolers who require augmentative and alternativecommunication (AAC). American Journal of Speech-Language Pathology,10, 81-94.

InclusionCriteria:4C

Ganz, J.B., Earles-Vollrath, T.L., Mason, R.A., Rispoli, M.J., Heath, A.K &Parker, R.I. (2011). An aggregate study of single-case research involvingaided aac: Participant characteristics of individuals with autism spectrumdisorders. Research in Autism Spectrum Disorders, 5, 1500-1509.


Ganz, J.B., Davis, J.L., Lund, E.M., Goodwyn, F.D., & Simpson, R.L.(2012). Meta-analysis of PECS with individuals with ASD: Investigation oftargeted versus non-targeted outcomes, participant characteristics, andimplementation phase. Research in Developmental Disabilities, 33, 406-418.


Ganz, J. B., Mason, R. A., Goodwyn, F. D., Boles, M. B., Heath, A. K., &Davis, J. L. (2014). Interaction of participant characteristics and type ofAAC with individuals with ASD: A meta-analysis. American journal onintellectual and developmental disabilities, 119(6), 516-535.


Gevarter, C., O’Reilly, M. F., Rojeski, L., Sammarco, N., Sigafoos, J.,Lancioni, G. E., & Lang, R. (2014). Comparing Acquisition of AAC-BasedMands in Three Young Children with Autism Spectrum Disorder UsingiPad® Applications with Different Display and Design Elements. Journal ofautism and developmental disorders, 44(10), 2464-2474.

ExclusionCriteria:3D

Hochstein, D. D., McDaniel, M. A., Nettleton, S., & Neufeld, K. H. (2003).The Fruitfulness of a Nomothetic Approach to Investigating AACComparing




Two Speech Encoding Schemes Across Cerebral Palsied and NondisabledChildren. American Journal of Speech-Language Pathology, 12(1), 110-120.Johnston, S. S., Davenport, L., Kanarowski, B., Rhodehouse, S., &McDonnell, A. P. (2009). Teaching sound letter correspondence andconsonant-vowel-consonant combinations to young children who useaugmentative and alternative communication. Augmentative andAlternative Communication, 25(2), 123-135.


Kouri, T. (1988). Effects of simultaneous communication in a child-directedtreatment approach with preschoolers with severe disabilities.Augmentative and Alternative Communication, 4(4), 222-232.


Lee, Y., Jeong, S. W., & Kim, L. S. (2013). AAC intervention using a VOCAfor deaf children with multiple disabilities who received cochlearimplantation. International journal of pediatric otorhinolaryngology, 77(12),2008-2013.


Lorah, E. R., Parnell, A., & Speight, D. R. (2014). Acquisition of sentenceframe discrimination using the iPad™ as a speech generating device inyoung children with developmental disabilities. Research in AutismSpectrum Disorders, 8(12), 1734-1740.


McNaughton, S. (1993). Graphic representational systems and literacylearning. Topics in Language Disorders, 13(2), 58-75.


Olin, A. R., Reichle, J., Johnson, L., & Monn, E. (2010). Examiningdynamic visual scene displays: Implications for arranging and teachingsymbol selection. American Journal of Speech-Language Pathology, 19(4),284-297.


Roberts, Joanne E [Ed], Chapman, Robin S [Ed] & Warren, Steven F [Ed].(2008). Speech and language development and intervention in Downsyndrome and fragile X syndrome. Speech and language development andintervention in Down syndrome and fragile X syndrome. Baltimore, MD,US: Paul H Brookes Publishing, US.


Roche, L., Sigafoos, J., Lancioni, G. E., O’Reilly, M. F., Schlosser, R. W.,Stevens, M., ... & Carnett, A. (2014). An evaluation of speech production intwo boys with neurodevelopmental disorders who received communicationintervention with a speech-generating device. International Journal ofDevelopmental Neuroscience, 38, 10-16.


Schwartz, I. S., Garfinkle, A. N., & Bauer, J. (1998). The picture exchangecommunication system communicative outcomes for young children withdisabilities. Topics in Early Childhood Special Education, 18(3), 144-159.


Sutton, A., Trudeau, N., Morford, J., Rios, M., & Poirier, M. A. (2010).Preschool-aged children have difficulty constructing and interpreting simpleutterances composed of graphic symbols. Journal of Child Language,37(01), 1-26.


Thistle, J. J., & Wilkinson, K. (2009). The effects of color cues on typicallydeveloping preschoolers' speed of locating a target line drawing:Implications for augmentative and alternative communication displaydesign. American Journal of Speech-Language Pathology, 18(3), 231-240.

InclusionCriteria: 3B

Trembath, D., Balandin, S., & Togher, L. (2007). Vocabulary selection for Inclusion



Australian children who use augmentative and alternative communication.Journal of Intellectual and Developmental Disability, 32(4), 291-301.

Criteria: 2A

Trudeau, N., Cleave, P. L., & Woelk, E. J. (2003). Using augmentative andalternative communication approaches to promote participation ofpreschoolers during book reading: a pilot study. Child Language Teachingand Therapy, 19(2), 181-210.


Wilkinson, K. M., Carlin, M., & Jagaroo, V. (2006). Preschoolers' speed oflocating a target symbol under different color conditions. Augmentative andAlternative Communication, 22(2), 123-133.


Wilkinson, K. M., & McIlvane, W. J. (2013). Perceptual factors influencevisual search for meaningful symbols in individuals with intellectualdisabilities and Down syndrome or autism spectrum disorders. Americanjournal on intellectual and developmental disabilities, 118(5), 353-364.



Appendix 2: Coding Protocol (WoE A)

Horner et al., 2005: The Use of Single-Subject Research to Identify Evidence-Based Practicein Special Education

Quality Indicators Within Single-Subject Research

Article Reference: Binger, C., & Light, J. (2006). Demographics of preschoolers whorequire AAC. Language, Speech, and Hearing Services in Schools, 37(3), 200-208.

Description of Participants and SettingParticipants are described with sufficient detail to allow others to select individuals withsimilar characteristics; (e.g., age, gender, disability, diagnosis).

Yes Age, gender, diagnosis and also descriptive information relating to thepresentation of the participants was given.

No

N/A

Unknown/Unable to Code

The process for selecting participants is described with operational precision.

Yes Criteria for participation was clearly described with 9 key points.

No

N/A


Critical features of the physical setting are described with sufficient precision to allowreplication.

Yes 7 pretend play scenarios were set up including washing a baby, having a tea party,playing with vehicles, playing with a farm, eating fast food, going to a birthday party, andcleaning the kitchen. The toys used in the scenarios were also described.

No

N/A


Overall Rating of Evidence: 3 2 1 0

Dependent VariableDependent variables are described with operational precision.

Yes Frequency of multi-symbol combination productions during 15-min play sessions.

No

N/A


Each dependent variable is measured with a procedure that generates a quantifiable index.

Yes

No


N/A


Measurement of the dependent variable is valid and described with replicable precision.

Yes

No

N/A


Dependent variables are measured repeatedly over time.

Yes

No

N/A


Data are collected on the reliability or inter-observer agreement associated with eachdependent variable, and IOA levels meet minimal standards

Yes 95%

No

N/A



Independent VariableIndependent variable is described with replicable precision.

Yes Aided AAC models during play scenarios

No

N/A


Independent variable is systematically manipulated and under the control of the experimenter.

Yes

No

N/A


Overt measurement of the fidelity of implementation for the independent variable is highlydesirable.

Yes

No

N/A




BaselineThe majority of single-subject research studies will include a baseline phase that providesrepealed measurement of a dependent variable and establishes a pattern of responding thatcan be used to predict the pattern of future performance, if introduction or manipulation ofthe independent variable did not occur.

Yes

No

N/A


Baseline conditions are described with replicable precision.

Yes

No

N/A



Experimental Control/internal ValidityThe design provides at least three demonstrations of experimental effect at three differentpoints in time.

Yes Baseline, intervention, generalisation & maintenance phases.

No

N/A


The design controls for common threats to internal validity (e.g., permits elimination of rivalhypotheses).

Yes

No

N/A


The results document a pattern that demonstrates experimental control.

Yes Data was collected over a range of sessions, and data was recorded on at least 3different points in time.

No

N/A




Social Validity

Experimental effects are replicated across participants, settings, or materials to establishexternal validity.

Yes Generalisation & maintenance phases.

No

N/A


The dependent variable is socially important.

Yes

No

N/A


The magnitude of change in the dependent variable resulting from the intervention is sociallyimportant.

Yes Increases in functional communication skills are very important, particularly forpre-school children in early stages of development and learning.

No

N/A


Implementation of the independent variable is practical and cost effective.

Yes AAC systems can be relatively simple to implement.

No

N/A


Social validity is enhanced by implementation of the independent variable over extended timeperiods, by typical intervention agents, in typical physical and social contexts.

Yes Maintenance phases took place at 2, 4 and 8 weeks following generalisationphase.

No

N/A



Average WoE A across the 6 judgement areas:

Sum of X / N = 16/6 = 2.7

X = individual quality rating for each judgement area

N = number of judgement areas



Appendix 3

WoE B: Methodological Relevance

This weighting considers whether the methodological design was suitable forevaluating the effectiveness of aided AAC on the functional communication skills ofpre-school children with additional needs. To decide the ratings given for WoE B, anevidence hierarchy was employed (Evans, 2003) to influence descriptors. Evidencehierarchies typically place studies with high threats to validity at the bottom (e.g.studies with no control group) and those less prone to threats to validity at the top(e.g. randomised control trials (RCTs)).

In order to receive a ‘High’ weighting an ‘active’ comparison group needs to beemployed as this allows the effectiveness of the intervention to be examined. Pre,post and follow up measures are necessary to receive a ‘high’ weighting as it notonly provides a baseline of participants and the impact of the intervention but alsoinformation as to whether the effects of the intervention are maintained when theintervention ceases.

In order to receive a ‘Medium’ weighting for methodological relevance a betweengroup study needs to have used a comparison group (e.g. waitlist control/nointervention), although the groups will not have not been accurately matched. Singlecase experimental designs may have also been used, in which case the levels ofexperimental control must be demonstrated (e.g. collecting data at various time-points during the intervention phase).

In order to receive a ‘Low’ weighting for methodological relevance the study needs tohave taken pre and post intervention measures, but used no comparison group.Non-experimental designs (e.g. observations, case reports) may also have beenused. Single case designs may have also been used, but would have notdemonstrated levels of experimental control (e.g. collecting data at various pointsduring the intervention phase).

WoE C: Study Focus Relevance

In order to receive a ‘High’ weighting for relevance the study sample must becomprised of pre-school children with a diagnosis of an additional need. Thesignificance of the use of AAC for the child must have been established, (they musthave limited communication skills). The functional communication skilloperationalized as the dependent variable must have been identified as relevant by achild’s teacher, parent or other caregiver.

In order to receive a ‘Medium’ weighting for relevance the study sample must becomprised of pre-school children with a diagnosis of an additional need. Either thesignificance of the intervention or the relevance of the dependent variable for thechild must have been established.

In order to receive a ‘Low’ weighting for relevance, the study sample must becomprised of pre-school children with a diagnosis of an additional needs. Thesignificance of the use of AAC for the child may have been established.


Appendix 4: Mapping the field

Author & Aims N Participants Location Design Type of AAC Setting1. Beck, Stoner, Bock, & Parton (2008)

This study compares use of the PictureExchange Communication System (PECS)and a Voice Output Communication Aide(VOCA) with four preschool children whowere either non-speaking or limited in theirability to speak and did not use an AACsystem to communicate functionally.

4 3 males:1 femaleAutism (n=2), S&Limpairment/ apraxia, (n=1)impairment, PDD-NOS(n=1)Ages not specified (pre-school >5 years)

USA Alternatingtreatmentsdesign

VOCA & PECS All attendingpre-schoolsettings

2. Binger & Light (2007)To evaluate the impact of using aided AACmodelling to support multi-symbolmessage production.

5 2 Males:3 females3:05 – 4:06 yearsPrader-Wili (n=1), DownsSyndrome (n=1), DiGeorgeSyndrome (n=1), Dev delay(n=2)

USA Singlesubject,multipleproberesearchdesign

Communicationboards

Pre-school

3. Bock, Stoner, Beck, Hanley, &Prochnow (2005)

The purposes of this study were to build onthe base of support for, and to comparethe relative effectiveness of two types ofAAC (PECS & VOCA) with preschoolchildren who have complex communicationneeds.

6 Males4 years oldDevelopmental delay (n=6)


VOCA & PECS Attendingpre-schoolsettings

4. Cihak, Smith, Cornett, & Coleman(2012)

To evaluate if the use of VM and PECSwould increase independentcommunicative initiations in preschool-agestudents

4 3 males:1 female3 years oldAutism (n=2) &Developmental delay (n=2)


PECS All attendingadevelopmental preschoolclassroom.


Author & Aims N Participants Location Design Type of AAC Setting5. Johnston, McDonnell, Nelson &

Magnavito (2003)To assess functional communication usingAAC devices in pre-school children inautism.

3 1 male: 2 femalesPre-school: 3-4 yearsDevelopmental delay, (n=1)Athetoid Cerebral palsy(n=1), severe multipledisabilities (n=1)

USA Multiplebaseline

Symbols/switch Inclusive pre-schoolclassrooms

6. Trembath, Balandin, Togher, &Stancliffe (2009)

To assess the effectiveness of twocommunication interventions for preschool-aged children with autism.

3 MalesAutism (n=3) 3,4 & 5 years

Australia Multiple-baseline

Naturalisticteaching vsNaturalisticteaching withSGD vsgeneralisation

Pre-school

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Case Study 1: An Evidence-Based Practice Review … · communication abilities can influence a number of factors in one’s life. ... The Picture Exchange Communication System